This invention relates to a ball joint and, particularly to a ball joint of the kind including a socket member having a recess therein for receiving a ball end of a ball member and a retaining ring for retaining the ball end in the recess.
Ball joints of the aforementioned kind are well known for connecting a mechanical part with another mechanical part and are widely used in various industrial fields.
Conventionally, the ball member and the socket member of the ball joint have been made of a metal such as steel however, recently, there has been proposed to form the socket member of synthetic resin for reducing the weight and the manufacturing costs. When the socket member is made of synthetic resin, another problem has been experienced namely that when a force acts on the ball member in the direction for extracting the ball end from the recess in the socket member, the force is transmitted to the socket member through the retaining ring which is usually formed of metal such as steel and, at that time, a stress concentration may sometimes occur which results the breakage of the socket member, and the ball member separates from the socket member.